Table 1.
Summary of histopathological changes in lungs of SH rats exposed to particulate matter or saline.
| Post-exposure time | 24 hr | 48 hr | |||||||
| Group | 1 | 4 | 5 | 6 | 1 | 4 | 5 | 6 | |
| Number examined | 9 | 9 | 9 | 9 | 10 | 10 | 10 | 10 | |
| Alveolar Mφ | minimal | 2 | 6 | 3 | 5 | 4 | 6 | 3 | - |
| slight | - | 2 | 5 | 1 | 1 | 4 | 2 | 6 | |
| moderate | - | 1 | 1 | 1 | - | - | 4 | 2 | |
| marked | - | - | - | - | - | - | - | 2 | |
| overall | 2 | 13 | 16 | 10 | 6 | 14 | 19 | 26 | |
| Inflammatory foci thick septa + alveolar Mφ | minimal | 6 | 4 | 3 | - | 6 | 2 | - | - |
| slight | 3 | 5 | 3 | 3 | 2 | 4 | - | - | |
| moderate | - | - | 3 | 3 | 2 | 4 | 7 | 3 | |
| marked | - | - | - | 3 | - | - | 3 | 7 | |
| overall | 12 | 14 | 18 | 27 | 16 | 22 | 33 | 37 | |
| BrdU score | number examined | 6 | 6 | 6 | 6 | 6 | 6 | 6 | 6 |
| minimal | 2 | - | - | - | 6 | 1 | - | - | |
| slight | 1 | 1 | - | - | - | 3 | - | - | |
| moderate | - | 3 | 3 | - | - | 2 | 3 | 2 | |
| marked | - | 2 | 2 | 3 | - | - | 3 | 2 | |
| strong | - | - | 1 | 3 | - | - | - | 2 | |
| overall | 4 | 19 | 22 | 27 | 6 | 13 | 21 | 24 | |
The lungs of SH rats exposed to saline (group1), 3 or 10 mg/kg of body weight RTD (respectively group 4 and 5) or 10 mg/kg of body weight EHC-93 (group 6) were examined at 24 or 48 hours post-exposure. In the overall score, a weight factor of 1 to 5 is included for the score minimal to strong. Abbreviations: Mφ – macrophages.